1. Field Of The Invention:
This invention relates to a velocity flow meter and more particularly to an apparatus which measures the velocity of high temperature pneumatically transported solids.
2. Description Of The Prior Art:
An important operation in several industries is the pneumatic transport of solids. A crucial variable in the transportation of solids is the velocity of the particles in the pipeline. The velocity of the particles is needed to calculate energy losses and erosion of the transport lines. The problem is compounded when high temperature solids, such as hot ash products from combustion and coal gasification units, are transported.
A known method of calculating particle velocities is by using estimations from correlations. This involves determination of the terminal velocity of the particle and calculating the particle velocity as the difference between the gas velocity and the terminal velocity. Correlations, which are based on estimates, do not provide accurate actual measurements of particle flow velocities.
It is known to calculate the velocity of a fluid by measuring a property of the fluid at each of two points a known distance apart. See U.S. Pat. Nos. 4,509,366; 3,789,663 and 4,402,230.
It is also known to measure solid matter mass flow by providing an upstream set of electrical devices and a downstream set of electrical devices connected to circuits which provide a measurement of the velocity of the material. U.S. Pat. No. 3,635,082.
U.S. Pat. No. 4,483,199 discloses using radiation sources and detectors to calculate solid mass measurements.
Despite these known devices, there still remains a need for a particle velocity meter which is accurate and reliable and which can be used in association with transporting high temperature solids.